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प्रश्न
Answer the following in detail.
Define friction and explain how it is useful to us.
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उत्तर
Friction is a force that opposes relative motion between two bodies/surfaces in contact with each other. Although friction opposes the motion, it also makes motion possible.
Friction helps us do many things like :
- It helps us in walking. In the absence of friction, we may slip or M.
- Cars and buses are able to move safely on roads due to the friction between the treaded tires of these vehicles and the surface of the road.
- Friction allows us to hold objects with our hands.
- It allows us to write on paper.
- Friction produces heat. In winter, when we rub our cold hands, the heat produced due to friction makes our hands warm.
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संबंधित प्रश्न
Suppose your writing desk is tilted a little. A book kept on it starts sliding down. Show the direction of frictional force acting on it.
Give examples to show that friction is both a friend and a foe.
When a glass rod is rubbed with a piece of silk cloth the rod ______.
Select the correct alternative.
Friction is reduced by
State two factors which directly affect the force of friction.
A body needs a force F1 just to start moving on a surface, a force F2 to continue its motion and a force F3 to roll on the surface. What is
- the static friction
- sliding friction and
- rolling friction? State whether F2 is equal, less than or greater than (1) F1 and (2) F3.
Fill in the blank.
Weight remaining the same, friction is independent of ............. of surface in contact.
Fill in the blank.
Friction is a type of .................
State if the following statement is true or false. Correct the statement if it is false.
Friction helps us to grip the objects in our hand.
Assertion: Friction always opposes the motion.
Reason: Whenever one surface moves or tries to move over another surface, the force of friction starts acting on the surfaces.
